JDM Subaru Legacy B4 BL5 Applied B Manual ECU Engine Computer – OEM Part #112300-0251 (5-Speed)

Restore factory-correct engine management and performance with this genuine JDM OEM Subaru ECU, part number 112300-0251, designed for the Subaru Legacy B4 BL5 Applied B models equipped with a 5-speed manual transmission. Imported directly from Japan and sold by J-Spec Auto Sports Inc., this engine control unit is the correct factory computer for BL5 manual applications and is increasingly difficult to find.

This OEM Subaru Legacy B4 ECU is calibrated specifically for manual-transmission EJ-series turbo setups, delivering precise fuel mapping, ignition timing, and throttle response exactly as Subaru intended. Using the correct Applied B ECU is critical—mismatched or automatic ECUs often cause drivability issues, CELs, improper fueling, or boost control problems.

The 112300-0251 ECU is ideal for customers replacing a faulty computer, completing a JDM BL5 Legacy B4 engine swap, or restoring a vehicle to OEM-correct configuration. JDM ECUs are highly sought after due to their origin from low-mileage Japanese vehicles, where strict inspection laws help preserve electronics in excellent condition.

Each ECU sold by J-Spec Auto Sports is tested and verified for functionality and authenticity, ensuring you receive a genuine Subaru unit—not a reflashed, cloned, or aftermarket substitute. As BL5 Legacy B4 parts continue to disappear from the market, this ECU represents both functional reliability and long-term value.

Key Features:

• Genuine JDM OEM Subaru ECU

• Part Number: 112300-0251

• Fits Subaru Legacy B4 BL5 Applied B

• 5-Speed Manual Transmission

• Factory Subaru programming (no aftermarket tune)

• Ideal for ECU replacement or JDM swaps

• Tested, verified, and authentic

• Rare and hard to source

Why Buy from J-Spec Auto Sports Inc.?

J-Spec Auto Sports Inc. specializes in premium JDM Subaru engines, ECUs, transmissions, and drivetrain components. Our reputation is built on honest descriptions, proper testing, and fast nationwide shipping. Enthusiasts and professional shops trust J-Spec Auto for genuine Japanese parts that work exactly as intended.

Nationwide shipping available
Limited inventory — OEM JDM Subaru ECUs sell fast

Secure this JDM Subaru Legacy B4 BL5 Applied B Manual ECU (112300-0251) today from J-Spec Auto Sports Inc. and complete your build the right way.